[V4,0/3] rpmsg signaling/flowcontrol patches

[Change from V3]:
Fixed review comments in previous set.

Sarannya S (3):
  rpmsg: core: Add signal API support
  rpmsg: glink: Add support to handle signals command
  rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support

 drivers/rpmsg/qcom_glink_native.c | 63 +++++++++++++++++++++++++++++++++++++++
 drivers/rpmsg/rpmsg_char.c        | 60 ++++++++++++++++++++++++++++++++-----
 drivers/rpmsg/rpmsg_core.c        | 20 +++++++++++++
 drivers/rpmsg/rpmsg_internal.h    |  2 ++
 include/linux/rpmsg.h             | 15 ++++++++++
 5 files changed, 152 insertions(+), 8 deletions(-)

On Mon, Nov 28, 2022 at 11:32:52PM +0530, Sarannya S wrote:
> [Change from V3]:
> Fixed review comments in previous set.
> 

Please do list the actual changes that you did. This ensures that new
people can focus on the new areas, if preferred, and that returning
reviewers get confirmation that their feedback was addressed.

Thanks,
Bjorn

> Sarannya S (3):
>   rpmsg: core: Add signal API support
>   rpmsg: glink: Add support to handle signals command
>   rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support
> 
>  drivers/rpmsg/qcom_glink_native.c | 63 +++++++++++++++++++++++++++++++++++++++
>  drivers/rpmsg/rpmsg_char.c        | 60 ++++++++++++++++++++++++++++++++-----
>  drivers/rpmsg/rpmsg_core.c        | 20 +++++++++++++
>  drivers/rpmsg/rpmsg_internal.h    |  2 ++
>  include/linux/rpmsg.h             | 15 ++++++++++
>  5 files changed, 152 insertions(+), 8 deletions(-)
> 
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>

On 11/30/2022 11:53 PM, Mathieu Poirier wrote:
> On Tue, 29 Nov 2022 at 02:29, Arnaud POULIQUEN
> <arnaud.pouliquen@foss.st.com> wrote:
>>
>> Hi Sarannya,
>>
>> On 11/28/22 19:02, Sarannya S wrote:
>>> Some transports like Glink support the state notifications between
>>> clients using flow control signals similar to serial protocol signals.
>>> Local glink client drivers can send and receive flow control status
>>> to glink clients running on remote processors.
>>>
>>> Add APIs to support sending and receiving of flow control status by
>>> rpmsg clients.
>>>
>>> Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
>>> Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>
>>> ---
>>>   drivers/rpmsg/rpmsg_core.c     | 20 ++++++++++++++++++++
>>>   drivers/rpmsg/rpmsg_internal.h |  2 ++
>>>   include/linux/rpmsg.h          | 15 +++++++++++++++
>>>   3 files changed, 37 insertions(+)
>>>
>>> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
>>> index d6dde00e..0c5bf67 100644
>>> --- a/drivers/rpmsg/rpmsg_core.c
>>> +++ b/drivers/rpmsg/rpmsg_core.c
>>> @@ -331,6 +331,24 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
>>>   EXPORT_SYMBOL(rpmsg_trysend_offchannel);
>>>
>>>   /**
>>> + * rpmsg_set_flow_control() - sets/clears serial flow control signals
>>> + * @ept:     the rpmsg endpoint
>>> + * @enable:  enable or disable serial flow control
>>> + *
>>> + * Return: 0 on success and an appropriate error value on failure.
>>> + */
>>> +int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool enable)
>>
>> Seems that you did not take into account comment in your V3 asking you to
>> add the destination address of the endpoint as parameter
> 
> I will not review this patchset until Arnaud's comment is addressed or
> a reason for the omission is provided.
> 
Arnaud, Mathieu,
Sorry, I did not find this comment in V3 patch.
I will update the patch by adding destination address as parameter.

Regards,
Sarannya
>>
>> Regards,
>> Arnaud
>>
>>> +{
>>> +     if (WARN_ON(!ept))
>>> +             return -EINVAL;
>>> +     if (!ept->ops->set_flow_control)
>>> +             return -ENXIO;
>>> +
>>> +     return ept->ops->set_flow_control(ept, enable);
>>> +}
>>> +EXPORT_SYMBOL(rpmsg_set_flow_control);
>>> +
>>> +/**
>>>    * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
>>>    * @ept: the rpmsg endpoint
>>>    *
>>> @@ -539,6 +557,8 @@ static int rpmsg_dev_probe(struct device *dev)
>>>
>>>                rpdev->ept = ept;
>>>                rpdev->src = ept->addr;
>>> +
>>> +             ept->flow_cb = rpdrv->flowcontrol;
>>>        }
>>>
>>>        err = rpdrv->probe(rpdev);
>>> diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
>>> index 39b646d..4fea45a 100644
>>> --- a/drivers/rpmsg/rpmsg_internal.h
>>> +++ b/drivers/rpmsg/rpmsg_internal.h
>>> @@ -55,6 +55,7 @@ struct rpmsg_device_ops {
>>>    * @trysendto:               see @rpmsg_trysendto(), optional
>>>    * @trysend_offchannel:      see @rpmsg_trysend_offchannel(), optional
>>>    * @poll:            see @rpmsg_poll(), optional
>>> + * @set_flow_control:        see @rpmsg_set_flow_control(), optional
>>>    * @get_mtu:         see @rpmsg_get_mtu(), optional
>>>    *
>>>    * Indirection table for the operations that a rpmsg backend should implement.
>>> @@ -75,6 +76,7 @@ struct rpmsg_endpoint_ops {
>>>                             void *data, int len);
>>>        __poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
>>>                             poll_table *wait);
>>> +     int (*set_flow_control)(struct rpmsg_endpoint *ept, bool enable);
>>>        ssize_t (*get_mtu)(struct rpmsg_endpoint *ept);
>>>   };
>>>
>>> diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
>>> index 523c98b..cc7a917 100644
>>> --- a/include/linux/rpmsg.h
>>> +++ b/include/linux/rpmsg.h
>>> @@ -64,12 +64,14 @@ struct rpmsg_device {
>>>   };
>>>
>>>   typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
>>> +typedef int (*rpmsg_flowcontrol_cb_t)(struct rpmsg_device *, void *, bool);
>>>
>>>   /**
>>>    * struct rpmsg_endpoint - binds a local rpmsg address to its user
>>>    * @rpdev: rpmsg channel device
>>>    * @refcount: when this drops to zero, the ept is deallocated
>>>    * @cb: rx callback handler
>>> + * @flow_cb: remote flow control callback handler
>>>    * @cb_lock: must be taken before accessing/changing @cb
>>>    * @addr: local rpmsg address
>>>    * @priv: private data for the driver's use
>>> @@ -92,6 +94,7 @@ struct rpmsg_endpoint {
>>>        struct rpmsg_device *rpdev;
>>>        struct kref refcount;
>>>        rpmsg_rx_cb_t cb;
>>> +     rpmsg_flowcontrol_cb_t flow_cb;
>>>        struct mutex cb_lock;
>>>        u32 addr;
>>>        void *priv;
>>> @@ -106,6 +109,7 @@ struct rpmsg_endpoint {
>>>    * @probe: invoked when a matching rpmsg channel (i.e. device) is found
>>>    * @remove: invoked when the rpmsg channel is removed
>>>    * @callback: invoked when an inbound message is received on the channel
>>> + * @flowcontrol: invoked when remote side flow control status is received
>>>    */
>>>   struct rpmsg_driver {
>>>        struct device_driver drv;
>>> @@ -113,6 +117,7 @@ struct rpmsg_driver {
>>>        int (*probe)(struct rpmsg_device *dev);
>>>        void (*remove)(struct rpmsg_device *dev);
>>>        int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
>>> +     int (*flowcontrol)(struct rpmsg_device *, void *, bool);
>>>   };
>>>
>>>   static inline u16 rpmsg16_to_cpu(struct rpmsg_device *rpdev, __rpmsg16 val)
>>> @@ -192,6 +197,8 @@ __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
>>>
>>>   ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
>>>
>>> +int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool enable);
>>> +
>>>   #else
>>>
>>>   static inline int rpmsg_register_device_override(struct rpmsg_device *rpdev,
>>> @@ -316,6 +323,14 @@ static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
>>>        return -ENXIO;
>>>   }
>>>
>>> +static inline int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool enable)
>>> +{
>>> +     /* This shouldn't be possible */
>>> +     WARN_ON(1);
>>> +
>>> +     return -ENXIO;
>>> +}
>>> +
>>>   #endif /* IS_ENABLED(CONFIG_RPMSG) */
>>>
>>>   /* use a macro to avoid include chaining to get THIS_MODULE */